<< Chapter < Page Chapter >> Page >

The more active an animal is, the more energy is needed to maintain that activity, and the higher its BMR or SMR. The average daily rate of energy consumption is about two to four times an animal’s BMR or SMR. Humans are more sedentary than most animals and have an average daily rate of only 1.5 times the BMR. The diet of an endothermic animal is determined by its BMR. For example: the type of grasses, leaves, or shrubs that an herbivore eats affects the number of calories that it takes in. The relative caloric content of herbivore foods, in descending order, is tall grasses>legumes>short grasses>forbs (any broad-leaved plant, not a grass)>subshrubs>annuals/biennials.

Animals adapt to extremes of temperature or food availability through torpor. Torpor is a process that leads to a decrease in activity and metabolism and allows animals to survive adverse conditions. Torpor can be used by animals for long periods, such as entering a state of hibernation    during the winter months, in which case it enables them to maintain a reduced body temperature. During hibernation, ground squirrels can achieve an abdominal temperature of 0° C (32° F), while a bear’s internal temperature is maintained higher at about 37° C (99° F).

If torpor occurs during the summer months with high temperatures and little water, it is called estivation    . Some desert animals use this to survive the harshest months of the year. Torpor can occur on a daily basis; this is seen in bats and hummingbirds. While endothermy is limited in smaller animals by surface to volume ratio, some organisms can be smaller and still be endotherms because they employ daily torpor during the part of the day that is coldest. This allows them to conserve energy during the colder parts of the day, when they consume more energy to maintain their body temperature.

Animal body planes and cavities

A standing vertebrate animal can be divided by several planes. A sagittal plane    divides the body into right and left portions. A midsagittal plane    divides the body exactly in the middle, making two equal right and left halves. A frontal plane (also called a coronal plane) separates the front from the back. A transverse plane (or, horizontal plane) divides the animal into upper and lower portions. This is sometimes called a cross section, and, if the transverse cut is at an angle, it is called an oblique plane. [link] illustrates these planes on a goat (a four-legged animal) and a human being.

Illustration A shows the planes of a goat body. The midsagittal plane runs through the middle of the goat from front to back, separating the right and left sides. The frontal plane also runs from front to back, but separates the upper half of the body from the lower half. The transverse plane runs across the middle of the goat, and separate the front and back halves of the body. Illustration B shows the planes of a human body. The midsagittal plane runs from top to bottom and separates the right and left halves of the body. The Frontal plane also runs from top to bottom and separates the front and back halves of the body. The Transverse plane dissects the middle of the body between the chest and abdomen, separating the top of the body from the bottom. The midline is an imaginary line running through the middle of the body, from top to bottom.
Shown are the planes of a quadruped goat and a bipedal human. The midsagittal plane divides the body exactly in half, into right and left portions. The frontal plane divides the front and back, and the transverse plane divides the body into upper and lower portions.

Vertebrate animals have a number of defined body cavities, as illustrated in [link] . Two of these are major cavities that contain smaller cavities within them. The dorsal cavity    contains the cranial and the vertebral (or spinal) cavities. The ventral cavity    contains the thoracic cavity, which in turn contains the pleural cavity around the lungs and the pericardial cavity, which surrounds the heart. The ventral cavity also contains the abdominopelvic cavity, which can be separated into the abdominal and the pelvic cavities.

Illustration shows a cross-sectional side view of the upper part of a human body. The entire head region above the eyes and to the back of the head and a long thin strip from this region down the back is shaded to indicate the dorsal cavity. The head is labeled cranial cavity and the long thin region down the back is the spinal cavity. A large oblong area shaded at the front of the body indicates the ventral cavity. It is labeled from top to bottom as thoracic cavity, diaphragm (thin line separating regions), abdominal cavity, and pelvic cavity. The abdominal and pelvic cavities are separated by a thin dashed line and together they are labeled the abdominopelvic cavity.
Vertebrate animals have two major body cavities. The dorsal cavity, indicated in green, contains the cranial and the spinal cavity. The ventral cavity, indicated in yellow, contains the thoracic cavity and the abdominopelvic cavity. The thoracic cavity is separated from the abdominopelvic cavity by the diaphragm. The thoracic cavity is separated into the abdominal cavity and the pelvic cavity by an imaginary line parallel to the pelvis bones. (credit: modification of work by NCI)

Career connections

Physical anthropologist

Physical anthropologists study the adaption, variability, and evolution of human beings, plus their living and fossil relatives. They can work in a variety of settings, although most will have an academic appointment at a university, usually in an anthropology department or a biology, genetics, or zoology department.

Non-academic positions are available in the automotive and aerospace industries where the focus is on human size, shape, and anatomy. Research by these professionals might range from studies of how the human body reacts to car crashes to exploring how to make seats more comfortable. Other non-academic positions can be obtained in museums of natural history, anthropology, archaeology, or science and technology. These positions involve educating students from grade school through graduate school. Physical anthropologists serve as education coordinators, collection managers, writers for museum publications, and as administrators. Zoos employ these professionals, especially if they have an expertise in primate biology; they work in collection management and captive breeding programs for endangered species. Forensic science utilizes physical anthropology expertise in identifying human and animal remains, assisting in determining the cause of death, and for expert testimony in trials.

Section summary

Animal bodies come in a variety of sizes and shapes. Limits on animal size and shape include impacts to their movement. Diffusion affects their size and development. Bioenergetics describes how animals use and obtain energy in relation to their body size, activity level, and environment.

Questions & Answers

what is nutrients
Patrick Reply
what are the types of skeleton
Tanyi Reply
endo skeleton and exo skeleton
Faith
or types of skeletons There is exo skeleton found in class insecta Exo skeleton found in phylum chordata and lastly hydrostatic skeleton found mainly in earth worms
Daniel
and hydrostatic skeleton
Godbless
what is life?
Jerson Reply
life is when any living thing breath or respirate.
Lucky
I want to join
Patrick
me too
Favour
me two
Monday
me too
Bengazy
me too
Maggie
I here
Yahaya
Does anybody knows another biology app that brings good understand
Lucky
give an example of a phylum where all members have open circulatory
Omoro Reply
anthropoda
Daniel
phylum Anthropoda
Daniel
how do u change the unit of temperature from degree celsius to degree Fahrenheit
Maggie
what are beneficial effects in industrial
Nnamani Reply
create employment
ibrahim
provide food
ibrahim
pollution
ibrahim
dirty the environment
ibrahim
pollution and lack of knowledge about how to manage waste
Alex
what is gametophyte
Ibrahim Reply
what is biology
Basiru Reply
Biology deals with the study of living organisms and their interactions with each other and the environment.
Quartey
biology simply means the study of living and non-livingthings.
Shamstar
what is the meaning of ubiquitous
Hamziyatu Reply
Under what topic is this question
fred
three branches of biology
Alexander Reply
what is the cell
Olajide Reply
what is life
Olajide
cell is the functional and structural unit of life
Shweta
life is a problem solving entity
Atanga
what is the characteristics of plant cell
Quaku
Describe the process that results in the formation of a tetrad.
Michael Reply
what is biology
Ndukwe Reply
biology is the study of life
Oghenemine
what is biology
Jimmy Reply
the study of life
Hamziyatu
what is the Biosphere?
Kabel Reply
I want to know what classifications of living organisms and their names
Quaku
are classified into plants and animals eukaryotic and prokaryotic cell.
Lokwe
what is biology?
Turabi Reply
what is the meaning of Biologists
Turabi
what is the meaning of Biologists
Turabi
what is the meaning of Biologists
Turabi
are those who are specialized in Biology
Nicode
Is the study of living things,
Kabel
what is the ecosystem?
Kabel
bio mean life logus means study so the study of living things or living organisms is called biology
Faraq
Ecosystem consists of the living organisms in a particular area together with the abiotic factors.
Quartey

Get the best Biology course in your pocket!





Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Biology' conversation and receive update notifications?

Ask